For about two years now I've been sketching on a racing game that has no enemies, it has cooperation by other players but never competition. How would that work? Actually, it's quite easy, and also quite fun if the racing experience is done well enough. That probably why other developers have also thought about this.
Noby Noby Boy is a long way from release and unnecessarily ugly in my oppinion, but it's interesting to see games that don't follow the classic patterns. As I've ranted about before, copying patterns from other games causes diminishing return in the amount of fun they will be to play. That's why innovation is so important.